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首页> 外文期刊>Journal of Volcanology and Geothermal Research >Syn- and posteruptive hazards of maar-diatreme volcanoes
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Syn- and posteruptive hazards of maar-diatreme volcanoes

机译：玛尔特极端火山的同发和后继危害

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摘要

Maar-diatreme volcanoes represent the second most common volcano type on continents and islands. This study presents a first review of syn- and posteruptive volcanic and related hazards and intends to stimulate future research in this field. Maar-diatreme volcanoes are phreatomagmatic monogenetic volcanoes. They may erupt explosively for days to 15 years. Above the preeruptive surface a relatively flat tephra ring forms. Below the preeruptive surface the maar crater is incised because of formation and downward penetration of a cone-shaped diatreme and its root zone. During activity both the maar-crater and the diatreme grow in depth and diameter. Inside the diatreme, which may penetrate downwards for up to 2.5 km, fragmented country rocks and juvenile pyroclasts accumulate in primary pyroclastic deposits but to a large extent also as reworked deposits. Ejection of large volumes of country rocks results in a mass deficiency in the root zone of the diatreme and causes the diatreme fill to subside, thus the diatreme represents a kind of growing sinkhole. Due to the subsidence of the diatreme underneath, the maar-crater is a subsidence crater and also grows in depth and diameter with ongoing activity. As long as phreatomagmatic emptions continue the tephra ring grows in thickness and outer slope angle. Synemptive hazards of maar-diatreme volcanoes are earthquakes, emption clouds, tephra fall, base surges, ballistic blocks and bombs, lahars, volcanic gases, cutting of the growing maar crater into the preemptive ground, formation of a tephra ring, fragmentation of country rocks, thus destruction of area and ground, changes in groundwater table, and potential renewal of emptions. The main hazards mostly affect an area 3 to possibly 5 km in radius. Distal effects are comparable to those of small emption clouds from polygenetic volcanoes. Synemptive effects on infrastructure, people, animals, vegetation, agricultural land, and drainage are pointed out. Posteruptive hazards concern erosion and formation of lahars. Inside the crater a lake usually forms and diverse types of sediments accumulate in the crater. Volcanic gases may be released in the crater. Compaction and other diagenetic processes within the diatreme fill result in its subsidence. This postemptive subsidence of the diatreme fill and thus crater floor is relatively large initially but will decrease with time. It may last millions of years. Various studies and monitoring are suggested for syn- and postemptive activities of maar-diatreme volcanoes empting in the future. The recently formed maar-diatreme volcanoes should be investigated repeatedly to understand more about their synemptive behaviour and hazards and also their postemptive topographic, limnic, and biologic evolution, and potential postemptive hazards. For future maar-diatreme emptions a hazard map with four principal hazard zones is suggested with the two innermost ones having a joint radius of up to 5 km. Areas that are potentially endangered by maar-diatreme emptions in the future are pointed out.
机译：玛尔至尊火山代表了大陆和岛屿上第二大最常见的火山类型。这项研究提出了关于上，下同流火山和相关危害的第一篇综述，并旨在激发该领域的未来研究。 Maar-diatreme火山是吞噬岩浆单基因火山。它们可能爆炸几天到15年。勃发前表面上方形成相对平直的特非拉环。在喷发前的表面之下，由于形成了圆锥形的钻石和它的根部区域并向下穿透，所以切割了玛尔火山口。在活动期间，maar火山口和diatreme的深度和直径都会增加。在最深处可能向下穿透达2.5公里的核砂岩内部，破碎的乡村岩石和幼年的火山碎屑岩堆积在主要的火山碎屑沉积物中，但在很大程度上也作为返工的沉积物。大量乡村岩石的喷出会导致diatreme根部区域质量下降，并导致diatreme填充物消退，因此diatreme代表了一种不断扩大的下沉孔。由于下面的非正常沉降，马氏坑是一个沉陷坑，随着活动的进行，其深度和直径也会不断增加。只要发磁空洞继续进行，则提夫拉环的厚度和外坡角都会增大。玛尔极端火山的突袭性危险是地震，空云，提菲拉坠落，高潮，弹道块和炸弹，拉哈斯，火山气体，将不断增长的玛尔火山口切入优先地面，形成特菲拉环，碎裂乡村岩石，因此会破坏面积和地面，改变地下水位，并可能重新产生空白。主要危害主要影响半径3到5公里的区域。远期影响可与多基因火山的小排空云相媲美。指出了对基础设施，人，动物，植被，农业用地和排水系统的暂时影响。后海报的危害涉及拉哈斯的侵蚀和形成。在火山口内通常会形成一个湖泊，火山口中会堆积各种类型的沉积物。火山口中可能释放出火山气体。异常填充物内部的压实作用和其他成岩作用导致沉降。极度填充的这种先发制人的沉陷和因此坑底的起初相对较大，但随着时间的推移会减少。它可能持续数百万年。建议进行各种研究和监测，以期对未来清空的玛尔至尊火山的继发性和后发性活动进行研究。最近形成的maar-diatreme火山应进行反复调查，以更多地了解其突触行为和危害，以及其后发地形，临nic和生物演化以及潜在的后发危害。对于未来的maar-diatreme清空，建议使用具有四个主要危险区域的危险地图，其中两个最里面的区域的联合半径最大为5 km。指出了将来可能受到不安全的空袭威胁的地区。

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